Spoligotyping of mycobacterium tuberculosis isolates from tuberculosis diagnosed patients at dilla university referral hospital and other private clinics, Southern Ethiopia

Objective: To assess Mycobacterium tuberculosis (M. tuberculosis) strains exsisting in Gedeo zone and the surrounding areas of the Southern Ethiopia using spoligotyping. Methods: A cross sectional study was carried out from February, 2012 to June, 2013 and 97 (76 sputum and 21 fine needle aspirate) samples were taken from tuberculosis diagnosed patients at Dilla University Referral Hospital and other private clinics. Culturing, region of difference (RD9) deletion typing and spoligotyping techniques were employed to isolate M. tuberculosis strains. Results: Growth of mycobacteria was observed in 35.1% (34/97). Speciation of isolates showed that 91.2% (31/34) of the isolates were M. tuberculosis. Further characterization led to the identification of 23 different spoligotype patterns of M. tuberculosis of which 61% and 39% displayed unique and cluster patterns, respectively. The most dominant shared type was spoligotype international type 53. Of the 23 strains, 12 have not been registered in the international spoligotyping database (SpolDB4). Seventy one percent of the strains belonged to the Euro-American lineage. Conclusions: This study revealed the existence of both genetically diverse and clustered M. tuberculosis strains from tuberculosis patients in the area, suggesting reactivation of infection and recent transmission, respectively. Molecular epidemiology of M. tuberculosis should be done nationwide in order to set appropriate control measures.